Photographer Ted Spagna glimpsed his subjects at their most vulnerable: while asleep. Starting in 1975, equipped with a time-lapse camera mounted to give him what he called a “God’s-eye view,” Spagna documented all manner of people — young and old, singles and couples, a cat — in deep slumber. The collected photos, about 30 per subject, are arranged chronologically, like a filmstrip, and have a voyeuristic quality to them. Mostly absent from the public eye since Spagna’s death in 1989, Sleep at long last retrieves the photographer’s project from obscurity and revives it in all its dreamy glory.